A hallucination (ICD-10-GM R44.-: Other symptoms affecting sensory perception and cognition) refers to a sensory illusion that is real to the individual. However, there is no underlying external stimulus. It can affect different senses.
One can classify hallucinations according to the ICD-10-GM as follows:
- Auditory hallucinations (ICD-10-GM R44.0).
- Visual hallucinations (ICD-10-GM R44.1)
- Other hallucinations (ICD-10-GM R44.2)
- Hallucinations, unspecified (ICD-10-GM R44.3)
The following other hallucinations are described:
- Gustative hallucination/gustatory hallucination (taste hallucination).
- Haptic hallucination – hallucination in the area of the skin, v.a. touch, stings, etc.
- Hypnagogic hallucination – mostly optical hallucinations that can occur during falling asleep.
- Hypnopompic hallucinations – mostly optical hallucinations that occur during the transition from sleeping to waking up.
- Kinesthetic hallucination – imagined perception of movement.
- Macropsychic hallucinations – visual hallucination in which people appear like giants (Gulliver hallucination/macro hallucination).
- Olfactive hallucinations/olfactory hallucination (olfactory hallucinations).
- Tactile hallucination – sensory illusions in the area of feeling.
- Zonaesthesias – sensory illusions involving one’s own body perception.
Hallucination can be symptom of many diseases (see under “Differential diagnoses”).
Gender ratio: women are more often affected than men.
The lifetime prevalence (disease frequency over a lifetime) of hallucinations is 5.2% worldwide (Germany: 1.8%).
